Adiposity, insulin and lipid metabolism in post-menopausal women

Abstract

OBJECTIVE:To investigate relationships between body fat and its distribution and carbohydrate and lipid tolerance using statistical comparisons in post-menopausal women. DESIGN: Sequential meal, postprandial study (600 min) which included a mixed standard breakfast (30 g fat) and lunch (44 g fat) given at 0 and 270 min, respectively, after an overnight fast. SUBJECTS: Twenty-eight post-menopausal women with a diverse range of body weight (body mass index (BMI), mean 27.2, range 20.5 -38.8 kg=m 2 ) and abdominal fat deposition (waist, mean 86.4, range 63.5 -124.0 cm). Women with BMI < 18 or > 37 kg=m 2 , age > 80 y and taking hormone replacement therapy (HRT) were excluded. MEASUREMENTS: Anthropometric measurements were performed to assess total and regional fat deposits. The concentrations of plasma total cholesterol, high density lipoprotein (HDL) cholesterol, triacylglycerol (TAG), glucose, insulin (ins), non-esterified fatty acids (NEFA) and apolipoprotein (apo) B-48 were analysed in plasma collected at baseline (fasted state) and at 13 postprandial time points for a 600 min period. RESULTS: Insulin concentrations in the fasted and fed state were significantly correlated with all measures of adiposity (BMI, waist, waist -hip ratio (W=H), waist -height ratio (W=Ht) and sum of skinfold thickness (SSk)). After controlling for BMI, waist remained significantly and positively associated with fasted insulin (r ¼ 0.559) with waist contributing 53% to the variability after multiple regression analysis. After controlling for waist, BMI remained significantly correlated with postprandial (IAUC) insulin (r ¼ 0.535) contributing 66% of the variability of this measurement. No association was found between any measures of adiposity and glucose concentrations, although insulin concentration in relation to glucose concentration (glucose -insulin ratio) was significantly negatively correlated with all measures of adiposity. A significant positive correlation was found between fasted TAG and BMI (r ¼ 0.416), waist (r ¼ 0.393) and Ssk (r ¼ 0.457) and postprandial (AUC) TAG with BMI (r ¼ 0.385) and Ssk (r ¼ 0.406). A significantly higher postprandial apolipoprotein (apo) B-48 response was observed in those women with high BMI ( > 27 kg=m 2 ). Fasting levels of NEFA were significantly and positively correlated with all measures of adiposity (except W=H). No association was found between cholesterol containing particles and any measure of adiposity. CONCLUSION: Hyperinsulinaemia associated with increasing body fat and central fat distribution is associated with normal glucose but not TAG or NEFA concentrations in postmenopausal women.

Lack of association between central adiposity and lipaemia in UK Sikh men

“…This supports findings from other groups on Caucasian subjects. 21,22,30,[45][46][47][48] However, it was observed that the Caucasian men in the present study had a significant positive associations between fasting glucose and BMI, waist and subscapular. Although the Sikh men had higher insulin resistance than the Caucasian men, they also presented with higher fasted insulin, which could have contributed to the lack of relationship between glucose and body fat distribution.…”

“…A limitation of this study was that a direct measure of body fat topography was not completed due to cost and availability of equipment; therefore, waist circumference was used as an index of central fat, which our group 30,48 and others 70,71 have identified as the most appropriate surrogate measure. Waist circumference has emerged as the strongest correlate to both the degree of obesity and accumulation of visceral adipose tissue, when anthropometric data were compared with direct imaging techniques in Caucasians, 70,71 yet to date it has not been determined whether this is the case in Indian Asian populations.…”

Methodology for studying postprandial lipid metabolism

“…Many studies are performed in young male adults, especially students. Studies that have compared young and middle aged subjects reveal marked effects of age on postprandial lipaemia (Jackson et al, 2003) Few of the early studies were performed in women, although recently studies have been specifically performed in female subjects (Murphy et al, 1995;Mekki et al, 1999;Lovegrove et al, 2002) to alleviate the lack of information in relation to sex differences. It is noteworthy that for a given meal, the postprandial lipid response is lower in women than men, owing to a higher clearance capacity (lipoprotein lipase activity).…”

“…Given the complexity of this syndrome involving insulin resistance, great care should be given to selection of subjects because of their metabolic heterogeneity. Some studies have been performed in obese/insulin-resistant subjects (Jeppesen et al, 1994;Couillard et al, 1998;Mekki et al, 1999;Guerci et al, 2000;Lovegrove et al, 2002;Harbis et al, 2004).…”

Introduction to the DISRUPT postprandial database: subjects, studies and methodologies

“…This type of postprandial protocol has been used to determine (a) the effect of chronic dietary fat manipulation or cereal/non-digestible carbohydrate supplement on the postprandial lipaemic response (studies 1-6, n = 257 subjects) [3,10,24,26,28], (b) influence of body size and shape on the postprandial lipaemic response (study 7, n = 28 subjects) [27,39] and (c) the acute impact of specific meal fatty acids in the first meal on the postprandial response to the second meal (studies 8 and 9, n = 20 subjects) [16][17][18][32][33][34]. An overview of the study designs are shown in Fig.…”